Cataracts are one of the oldest and most common afflictions of humankind. Most people will develop cataracts with aging, and cataract removal is the most common surgical procedure in the world. The good news about cataracts is that the treatment options are among the most successful in all of medicine. Scheie’s cataract surgeons are experts in treating complicated cases, and cataracts in combination with other eye problems, and use the proven techniques and lenses.
What is a Cataract?
To understand what a cataract is it may be helpful to learn some basic facts about how the eye works. Light from the object you are looking at passes through the cornea, the clear covering over the iris, through the pupil, the black opening in the center of the iris, then through the lens.
The lens, normally a crystal clear structure located behind the pupil and iris, focuses light on the retina, much as the lens in a camera focuses light. The retina acts as the film in a camera and forms the image. The image is transmitted by the optic nerve to the brain, where the actual process of seeing takes place.
The term cataract refers to a clouding or loss of transparency of the lens. As clouding progresses, light has difficulty passing through the lens. This results in dim, distorted or blurred images on the retina and decreased vision, similar to looking through a dirty window.
Cataracts do not grow. A cataract is not skin over the eye, nor is it a tumor. A cataract progresses because of increasing cloudiness of the lens. There is no way of predicting how rapidly a cataract will progress. Some develop slowly over a period of many years, while others progress rapidly. At present, no treatment will slow or stop the progression of a cataract.
Cause of Cataracts
The cause of cataracts is unknown. Most cataracts seem to be the result of the aging process, and most occur in individuals over age 65. However, cataracts can occur at any age. In fact, the second most common age group affected is the very young. Their cataracts are congenital in nature. People on chronic doses of steroids (such as for asthma) and smokers are at higher risk. A cataract may be caused or accelerated by conditions such as injury, inflammation inside the eye, certain disorders of blood chemistry and some drugs.
Symptoms of Cataracts
Many people have early cataracts and are unaware of them. The mere presence of a cataract does not mean you need surgery. If you see well enough to do most things you want to do, then you most likely do not need to have surgery. On the other hand, if your decreased vision interferes significantly with your lifestyle, surgery may be beneficial. Cataract surgery can be done at any time and at any age. In the vast majority of cases, it is an elective procedure. The decision to have the operation must be made by you based on advice from your ophthalmologist.
The lens may be divided into three parts: the central nucleus, the surrounding cortex and the enveloping capsule. Each part - independently or together - may cloud or become opaque, resulting in a cataract.
Some cataracts decrease distance vision, while others predominantly affect near vision, and still others affect both. Early cataracts may affect the vision more in certain lighting conditions, either bright light or darkness. Common symptoms of early cataracts include glare, halos, and a marked decrease in vision while driving at night. Depending on your own visual needs, a developing cataract may or may not interfere with your normal lifestyle.
Cataracts can be diagnosed through various tests performed by an ophthalmologist. These tests may include the standard ophthalmic exam, which examines the patient's visual acuity, or the slit lamp examination, which examines the front structure of the eye. Although moderately rare, other tests may also be performed, including the glare test, contrast sensitivity test, potential visual test, and specular microscopic of the cornea.
Years ago, a cataract had to ripen before removal. Now, with new surgical techniques, a cataract may be removed at any stage in which a significant visual impairment is evident.
Removal of the Cataract
There are several ways to remove a cataract. The most commonly used method is the phacoemulsification technique where the cloudy lens is broken up, using an ultrasound probe that allows removal of the pieces through a tiny incision. A soft, plastic intraocular lens is then carefully inserted, and visual recovery is very rapid. The incision may not even require sutures.
The second, less commonly used technique, is extra capsular lens extraction. With the extra capsular technique, a larger incision is necessary, and the whole cataract is removed intact, rather than breaking it up with ultrasound. Visual rehabilitation takes somewhat longer than it does with the phacoemulsification method, because a larger incision is required. Most often, the phacoemulsification technique is used, but each technique for cataract removal has its advantages. The method to be used on your cataract is the one that your ophthalmologist feels is the best and safest in your particular case.
Insertion of Intraocular Lens
With both of these techniques, the side and back of the capsule, in the form of a bag, is left behind. This capsular bag is what holds the artificial lens in place. However, in some people, the posterior aspect of this bag can become opaque. If the bag is opaque enough, it can cause symptoms similar to the original cataract - loss of vision, glare, halos, etc. Some people refer to this as a secondary cataract, but its real name is known as posterior capsule opacification.
This opacified capsule then may be opened using a special laser called the YAG laser. The laser simply tears an opening in the capsule but usually does not hurt the artificial lens. When people say they had their cataracts removed by a laser, this technique is usually what they are referring to. The laser procedure is usually performed in the doctor’s office under topical eye drops. The post-procedure restrictions are usually minimal.
After a cataract operation, because of the removal of the lens from within the eye, a loss of focusing power results. The majority of patients are candidates for lens implants. An intraocular lens is used with either type of cataract procedure. The artificial lens is usually made of PMMA, silicone or acrylic materials. All types of materials have a long and very good safety record of use within the eye. Even with an implant, however, you still may need glasses for reading or distance.
Occasionally, your surgeon may not be able to insert an implant during the operation. If this happens, you might have to wear a contact lens or have a secondary intraocular lens implant later.
Preparation for Surgery
A complete outpatient medical examination, including X-rays and laboratory tests, is performed during the week before surgery. You then come to the surgical center on the day of surgery, have your cataract removed and go home the same day. In special circumstances, usually because of a medical illness, cataract surgery may be performed on an inpatient basis.
Most cataract surgery is done under either topical or local anesthesia with intravenous sedation. Patients may fall asleep during the operation and awake to find that the operation is finished.
Immediately Following Surgery
Following surgery, you are out of bed almost immediately. The eye may be patched for one night. Medications are used to prevent infection and to help the healing process. For about three weeks after surgery, a plastic shield must be worn at night and protective glasses during the day to prevent accidental injury to the eye.
Your surgeon will see you as an outpatient the day after surgery and perhaps three or four times more during the two months after surgery. It takes about two months to heal. During that time, your vision may vary. At home, you should observe a few precautions:
- No heavy lifting
- Avoid bending over with your head below your knees
- No rubbing or scratching the operative eye
- No sleeping on the operative eye
- Avoid dusty areas
- Use your eye drops on schedule
Cataract surgery is successful most of the time. Unfortunately, even in cases with an excellent surgical outcome, vision after the operation is sometimes poor because of disease elsewhere in the eye. Frequently, the existence of such a condition cannot be detected before surgery because the back of the eye cannot be seen through a cataract.
Risks of Cataract Surgery
Cataract surgery, like any other kind of surgery, involves the risk of complications. Bleeding, infection or poor healing may occur. Any of these circumstances may interfere with vision, and may even lead to blindness. The likelihood that any of these events will happen is very small, and every precaution against their occurrence is taken.
Of the many hundreds of thousands of cataract operations performed every year in this country, about 98% of patients with otherwise healthy eyes have useful vision restored.